the same???

[~laser_craver~]

i feel stupid asking this but are a safc and a fuel pressure regulator the same thing??? i know u need to have a fuel pressure regulator to run a 255 walbro but is a safc the same thing???

ryan

 

[spoolup]

no they are not the same, the FPR is a device that regulates the amount of pressure in your fuel line (IE it needs to be placed after the fuel rail). A SAFC is a piggy back device that alters the airflow signal going to the ECU to trick the ECU to give or take away fuel. there are seveal write up in the tech articles above that explain how a SAFC or piggy back work. Maybe read thru them.

Also you do not NEED, a afpr for the 255, it is recommended, myfuel pressure read the same until I got to ABOUT 3 lbs of boost, which means at idle, (vacuum) I was dumping too much fuel into her, causing odd fuel trims.

The SAFC would be used to increase or decrease the amount of fuel as mentioned above to compensate for bigger injectors, and to lean it out just a bit to add power. I HIGHly suggest reading the above mentioned tech articals, since improper use of either device could possibly damage your engine.

 

[~laser_craver~]

so could i run a safc and not run a fpr??? or should i run both of them?

ryan

 

[Sean485]

You will want both, the safc is nice because you can tune for injectors that are "close" to the same size as stockers, but it also messes with the timing advance the ecu gives out and can cause knock if you try to run too large of injectors without some other form of compensation. The FPR lets you raise/lower fuel pressure to bump the entire fuel curve up or down and since the ecu cant "see" fuel pressure it wont affect the timing advance the ecu gives out. With some practive and using the 2 cooperativly and adjusting your base ignition timing correctly, you can get alot better tune than with just one or the other

 

[~laser_craver~]

thankx

ryan